1. Field of the Invention
The present invention relates to a microorganism capable of degrading a polylactic acid resin and a method of degrading a polylactic acid resin by a novel biological treatment using the above microorganism.
2. Discussion of the Related Art
In recent years, disposal of plastic wastes has been of great concern. Although burning and landfill are major methods of disposal, biodegradation is drawing attention, since these conventional methods are problematic, in that, for instance, burning accelerates global warming, and landfill site availability is decreasing. Also, as a new-generation plastic material, a polylactic acid resin is now being developed for various applications; it is very likely that disposal of the polylactic acid resin waste will pose a difficult problem as with currently used plastics in the near future.
A polylactic acid resin, a polymer that undergoes hydrolysis in aqueous systems, is currently applied to medicines and medical materials. Because the polylactic acid can be synthesized via lactic acid fermentation from recyclable resources, such as starch, it is being remarked as a biodegradable plastic material as a substitute for general-purpose plastics, which are difficult to degrade under environment conditions. The polylactic acid resins occur in the form of a poly-L-lactic acid, a poly-D-lactic acid, a poly-DL-lactic acid or copolymers with other polymers, depending on the kind of constituent monomer.
The polylactic acid resin is known to undergo enzymatically accelerated hydrolysis. However, there have been no known arts regarding microorganisms capable of directly biodegrading a polylactic acid resin or wastes thereof. Also, there have been no known arts regarding methods of degrading a polylactic acid resin using microorganisms.
Accordingly, an object of the present invention is to provide a microorganism capable of directly biodegrading a polylactic acid resin or plastics containing it.
Another object of the present invention is to provide a method of degrading a polylactic acid resin using the above microorganism.
These and other objects of the present invention will be apparent from the following description.